* to find a free region that is of my size and has not
* been reserved.
*
- * on succeed, it returns the reservation window to be appended to.
- * failed, return NULL.
*/
-static struct ext3_reserve_window_node *find_next_reservable_window(
+static int find_next_reservable_window(
struct ext3_reserve_window_node *search_head,
- unsigned long size, int *start_block,
+ struct ext3_reserve_window_node *my_rsv,
+ struct super_block * sb, int start_block,
int last_block)
{
struct rb_node *next;
struct ext3_reserve_window_node *rsv, *prev;
int cur;
+ int size = my_rsv->rsv_goal_size;
/* TODO: make the start of the reservation window byte-aligned */
/* cur = *start_block & ~7;*/
- cur = *start_block;
+ cur = start_block;
rsv = search_head;
if (!rsv)
- return NULL;
+ return -1;
while (1) {
if (cur <= rsv->rsv_end)
* space with expected-size (or more)...
*/
if (cur > last_block)
- return NULL; /* fail */
+ return -1; /* fail */
prev = rsv;
next = rb_next(&rsv->rsv_node);
- rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
+ rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node);
/*
* Reached the last reservation, we can just append to the
* return the reservation window that we could append to.
* succeed.
*/
- *start_block = cur;
- return prev;
+
+ if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
+ rsv_window_remove(sb, my_rsv);
+
+ /*
+ * Let's book the whole avaliable window for now. We will check the
+ * disk bitmap later and then, if there are free blocks then we adjust
+ * the window size if it's larger than requested.
+ * Otherwise, we will remove this node from the tree next time
+ * call find_next_reservable_window.
+ */
+ my_rsv->rsv_start = cur;
+ my_rsv->rsv_end = cur + size - 1;
+ my_rsv->rsv_alloc_hit = 0;
+
+ if (prev != my_rsv)
+ ext3_rsv_window_add(sb, my_rsv);
+
+ return 0;
}
/**
* @sb: the super block
* @group: the group we are trying to allocate in
* @bitmap_bh: the block group block bitmap
+ *
*/
static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
int goal, struct super_block *sb,
struct ext3_reserve_window_node *search_head;
int group_first_block, group_end_block, start_block;
int first_free_block;
- int reservable_space_start;
- struct ext3_reserve_window_node *prev_rsv;
struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
unsigned long size;
+ int ret;
+ spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
group * EXT3_BLOCKS_PER_GROUP(sb);
start_block = goal + group_first_block;
size = my_rsv->rsv_goal_size;
+
if (!rsv_is_empty(&my_rsv->rsv_window)) {
/*
* if the old reservation is cross group boundary
my_rsv->rsv_goal_size= size;
}
}
+
+ spin_lock(rsv_lock);
/*
* shift the search start to the window near the goal block
*/
* need to check the bitmap after we found a reservable window.
*/
retry:
- prev_rsv = find_next_reservable_window(search_head, size,
- &start_block, group_end_block);
- if (prev_rsv == NULL)
- goto failed;
- reservable_space_start = start_block;
+ ret = find_next_reservable_window(search_head, my_rsv, sb,
+ start_block, group_end_block);
+
+ if (ret == -1) {
+ if (!rsv_is_empty(&my_rsv->rsv_window))
+ rsv_window_remove(sb, my_rsv);
+ spin_unlock(rsv_lock);
+ return -1;
+ }
+
/*
* On success, find_next_reservable_window() returns the
* reservation window where there is a reservable space after it.
* block. Search start from the start block of the reservable space
* we just found.
*/
+ spin_unlock(rsv_lock);
first_free_block = bitmap_search_next_usable_block(
- reservable_space_start - group_first_block,
+ my_rsv->rsv_start - group_first_block,
bitmap_bh, group_end_block - group_first_block + 1);
if (first_free_block < 0) {
* no free block left on the bitmap, no point
* to reserve the space. return failed.
*/
- goto failed;
+ spin_lock(rsv_lock);
+ if (!rsv_is_empty(&my_rsv->rsv_window))
+ rsv_window_remove(sb, my_rsv);
+ spin_unlock(rsv_lock);
+ return -1; /* failed */
}
+
start_block = first_free_block + group_first_block;
/*
* check if the first free block is within the
- * free space we just found
+ * free space we just reserved
*/
- if ((start_block >= reservable_space_start) &&
- (start_block < reservable_space_start + size))
- goto found_rsv_window;
+ if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end)
+ return 0; /* success */
/*
* if the first free bit we found is out of the reservable space
- * this means there is no free block on the reservable space
- * we should continue search for next reservable space,
+ * continue search for next reservable space,
* start from where the free block is,
* we also shift the list head to where we stopped last time
*/
- search_head = prev_rsv;
+ search_head = my_rsv;
+ spin_lock(rsv_lock);
goto retry;
-
-found_rsv_window:
- /*
- * great! the reservable space contains some free blocks.
- * if the search returns that we should add the new
- * window just next to where the old window, we don't
- * need to remove the old window first then add it to the
- * same place, just update the new start and new end.
- */
- if (my_rsv != prev_rsv) {
- if (!rsv_is_empty(&my_rsv->rsv_window))
- rsv_window_remove(sb, my_rsv);
- }
- my_rsv->rsv_start = reservable_space_start;
- my_rsv->rsv_end = my_rsv->rsv_start + size - 1;
- my_rsv->rsv_alloc_hit = 0;
- if (my_rsv != prev_rsv) {
- ext3_rsv_window_add(sb, my_rsv);
- }
- return 0; /* succeed */
-failed:
- /*
- * failed to find a new reservation window in the current
- * group, remove the current(stale) reservation window
- * if there is any
- */
- if (!rsv_is_empty(&my_rsv->rsv_window))
- rsv_window_remove(sb, my_rsv);
- return -1; /* failed */
}
/*
int goal, struct ext3_reserve_window_node * my_rsv,
int *errp)
{
- spinlock_t *rsv_lock;
unsigned long group_first_block;
int ret = 0;
int fatal;
ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal, NULL);
goto out;
}
- rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
/*
* goal is a group relative block number (if there is a goal)
* 0 < goal < EXT3_BLOCKS_PER_GROUP(sb)
* then we could go to allocate from the reservation window directly.
*/
while (1) {
- struct ext3_reserve_window rsv_copy;
-
- rsv_copy._rsv_start = my_rsv->rsv_start;
- rsv_copy._rsv_end = my_rsv->rsv_end;
-
- if (rsv_is_empty(&rsv_copy) || (ret < 0) ||
- !goal_in_my_reservation(&rsv_copy, goal, group, sb)) {
- spin_lock(rsv_lock);
+ if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
+ !goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb)) {
ret = alloc_new_reservation(my_rsv, goal, sb,
group, bitmap_bh);
- rsv_copy._rsv_start = my_rsv->rsv_start;
- rsv_copy._rsv_end = my_rsv->rsv_end;
- spin_unlock(rsv_lock);
if (ret < 0)
break; /* failed */
- if (!goal_in_my_reservation(&rsv_copy, goal, group, sb))
+ if (!goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb))
goal = -1;
}
- if ((rsv_copy._rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
- || (rsv_copy._rsv_end < group_first_block))
+ if ((my_rsv->rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
+ || (my_rsv->rsv_end < group_first_block))
BUG();
ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal,
- &rsv_copy);
+ &my_rsv->rsv_window);
if (ret >= 0) {
my_rsv->rsv_alloc_hit++;
break; /* succeed */
projects / linux-2.6-omap-h63xx.git / blobdiff